Add `geocoder_tokens` option for normalizing queries per index

Adds ability for each index to specify a query token mapping, e.g. remapping a query independently for when that index is searched:

    # places
    geocoder_tokens: {
        "saint": "st"
    }
    saint lucia drive => st lucia drive

    # address
    geocoder_tokens: {
        "drive": "dr"
    }
    saint lucia drive => saint lucia dr